G-Comp 1970-73 Camaro/Firebird Torque Arm Rear Suspension Kit

$2,222.00

Solid Axle Rear Suspension Type, Coilover Spring Type

This torque are rear suspension kit is specifically designed for the 1970-73 Camaro/Firebird
It replaces factory leaf springs with coil-over shocks within a compact design
Will fit up to 10″ wide wheel and 305/35/19 tires without cutting into body/wheel tub of your F-body
Includes an adjustable Panhard bar to control lateral movement and roll center height
Engineered to be 100% bolt-in, with no cutting of the vehicle to install

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SKU: F3YRS31630 Category: Car Chassis & Suspension Kits

Description

Product Summary

Solid Axle Rear Suspension Type, Coilover Spring Type

This torque are rear suspension kit is specifically designed for the 1970-73 Camaro/Firebird
It replaces factory leaf springs with coil-over shocks within a compact design
Will fit up to 10″ wide wheel and 305/35/19 tires without cutting into body/wheel tub of your F-body
Includes an adjustable Panhard bar to control lateral movement and roll center height
Engineered to be 100% bolt-in, with no cutting of the vehicle to install

Installation Tips

Pictured with optional coil-overs and center section (available with a clutch-type differential or a gear-type differential). Center section and coil-overs are shown for illustration purposes only and are not included with the kit, but available separately.
Double splined axles are not included but available separately. 60″ housing provided will utilize axle lengths of 28.5″ & 33″. Axle part #s suggested are 31-spline 910-50031-28.5 & 910-50031-33
Exhaust routing is unique to each vehicle and will need to be determined by end-user. Compact design allows multiple options.
Kit includes:
- Grand National 9″ rear end 60″ housing (requires 28.5″ & 33″ axles)
- Floater wheel hub components (hubs, flanges, bearings, seals, hardware)
- Rear cross member
- Subframe connectors and crossmember with hardware
- Trailing arms and brackets with hardware
- 52” torque arm with hardware
- Panhard bar with hardware
- 650 lb. x 26” Sway bar with arms, links, and hardware
- Shock mount hardware
- Drill guide and instruction sheet

Details

What else have you come to expect from the Speedway Motors G-Comp product line than a 100% bolt-on, economical, track-tested suspension for your 70-73 Camaro? G-Comp by Speedway has erased the line between street classics and track-only race cars. The G-Comp torque arm rear suspension system replaces your factory leaf spring suspension with a 2″ lower coilover torque arm style suspension for improved ride and rear axle stability, numerous ride height adjustments, and a heavy-duty suspension to handle all of your spirited driving. This suspension system bolts to factory locations and avoids cutting into your F-Body floor pans. Track tested and engineered for greatness, and precision-built in Lincoln, Nebraska.

From the factory, your stock 2nd Generation Camaro rear suspension is lacking. Second generation F-body cars are notorious for a poor weight bias – with 58% front weight and 42% rear – you can see just how difficult it can be to overcome this weight unbalance and make one of these cars handle through modern spirited street driving or track duty. A heavy front nose creates a handful of a car when trying to power through corners because of the reduced weight over the rear axle, making it harder to control under power and keep both tires planted to the ground when needed. Our clean-sheet torque arm rear suspension design removes all of these shortcomings from the equation. The 52″ torque arm moves the main rear axle pivot point forward – increasing the dynamic load on the rear tires, greatly improving traction and rear axle stability. This makes for a very stout suspension design for high horsepower cars, autocross, and road course cars, and dedicated drag race builds.

Our G-comp suspension checks all the boxes, with additional key benefits such as an adjustable panhard bar controlling lateral rear axle movement and a heavy-duty adjustable torsion style sway bar allowing you to dial in the exact rear suspension setup you need. The clean-sheet design allows for endless adjustability – ride height, roll center, instant center, pinion angle, and wheelbase are all adjustable for your suspension tuning needs

Features

100% bolt-in – no cutting of the vehicle to install
Replaces factory leaf springs with coil-over shocks within a compact design
Designed ride height is 2″ lower than stock, easily adjustable with coil overs
Fit up to 10″ wide wheel and 305/35/19 tires without cutting into body/wheel tub of your F-body
Lower shock mount has two positions to accommodate multiple length shocks
Adjustable Panhard bar to control lateral movement and roll center height
1-1/4” x .125” wall DOM trailing arms with rebuildable and greaseable 2” Johnny Joints®
Fabricated steel 9″ Ford Grand National (floater style) rear end housing
60” overall rear end width, hub face to hub face (unique to 2nd generation Camaro)
Includes sub-frame connectors that bolt directly to factory front subframe mounts
All hardware included
Adjustable for near-endless setup variations:
- Ride height
- Roll center by moving the Panhard bar in one of three positions on each end for a 1.75” adjustment at desired ride height
- Instant center using one of three lower arm positions for a 4” total movement
- Pinion angle with serrated hardware (4 degrees of total adjustment)
- Sway bar rate – 11 spring rates to choose from with 650 supplied
- Alignment capability for positive tracking and tire wear
Designed to complement the G-Comp front end kit and handle the highest level of load for street, road course, autocross, and Sport/Pro touring applications
Rear crossmember is made from .120″ wall steel tube and is attached to inner frame rails and body
Front Cross Member is .109” wall and clearance for any transmission
Chassis brace reduces chassis flex and provides a rigid mount for the trailing arms
Kit works with both stock wheel wells and mini-tubs
Kit allows room for both OEM fuel tanks or custom fuel cells
Rear-end housing has sway bar, trailing arm, and torque arm mounts installed
Speedway Grand National 5 x 4-3/4 rear hubs with all bearings, seals and hardware included
Kit includes a 7/8″ x 26” solid torsion bar style sway bar. 622875126 available in eleven rates from 650 to 900
Sway bar connects to the rear end housing with 7-1/2″ long aluminum arms
All sway bar links and hardware is included

Application

G-Comp rear suspension kits utilize a full floater Ford 9 Inch rear axle setup. Our floating rear axle design, using Grand national style hub and bearing assemblies is technology taken right from the NASCAR playbook – and for good reason. The Grand national hub is centered around a much larger, heavy-duty bearing that can handle the additional abuse that high-horsepower street and track cars deliver. The larger bearing surface also carries the torsional load placed on the wheel when cornering more efficiently than a traditional one-piece cast hub and axle design. In addition to a larger bearing carry the load, our aluminum Grand national hubs reduce rotating mass without sacrificing strength. The G Comp Torque Arm Rear Suspension allows you to run up to a 305/35/19 tire and a 10″ wide wheel with a maximum of 6.5″ backspacing without having to cut into the stock F-body body/wheel tubs.

Rear-axle housing includes caliper brackets that accept calipers with a 5.25″ mounting spacing, such as the Wilwood Dynalite 8351206816. Floater rear hubs accept 12.19″ x 0.81″ brake rotors with an 8 x 7.00″ bolt pattern, such as the Speedway Motors Pro-Lite 91031908. Combine this caliper and rotor combo with Wilwood Poly-D Brake Pads 8353991 for a complete rear brake setup. This brake combo is a great value for spirited street driving as well as entry-level autocross and road course competitions.

Shock length and spring rate will depend on how you set the car up (ride height, vehicle weight, ride stiffness, etc.).

Here’s what we recommend as a starting point:

Shocks – 5/8″ Bolt, 5″ Stroke
- Pro Touring Fixed Valve Coil-Over Shock
  - Static Shock length 13-14″
Springs – 2-5/8″ ID Springs
- AFCO 2-5/8″ Coil-Over Springs
  - Spring Rates: 350lb for street driving, 500lb for competition

Guides & Documents

KEY SPECS
MFG. Part #	91617081
Brand	G-Comp By Speedway
Rear Suspension Type	Solid Axle
Trailing Arm Style	Torque Arm
Spring Type	Coilover
Bolt-On	Yes
Axle Housing Included	Yes
Hardware Included	Yes

GENERAL
Finish	Raw
Sold in Quantity	Kit
Notes	Pictured with optional 3rd member and coilovers, sold separately.

Front Spring Choices for Traditional Straight Axle Hot Rods

Building a Traditional Hot Rod Front End Requires Choosing the Right Transverse Leaf Spring

Ford used a straight axle front suspension design with a single transverse mounted leaf spring from just after the turn of the century until the late 1940s. This application range covers just about every popular pre-war Ford hot rod body style we all know and love. Model Ts, Model As, ’32 Fords, and so on. While there are dozens of aftermarket frame and suspension options and complete kit car build variants of these models today that use independent front suspension (IFS), if you are looking to build a traditional-style street rod on any of these models you’re going to be running a straight front axle with either standard or split wishbones (learn more about wishbones in this Speedway Motors Toolbox guide) and you are going to have to pick a leaf spring that will work with your axle of choice and your intended ride height.

Split Wishbone Spring Over Straight Axle Suspension

The traditional straight axle suspension is a very old design, no doubt, and it does have its disadvantages, such as noticeable bump steer and lack of lateral location/support of the front axle. That said, there are plenty of reasons to still run a solid axle suspension with a transverse leaf spring. Of course, keeping a traditional hot rod look is at the top for most enthusiasts, as it is front and center and quite visible on the car and frankly just looks “right” for these models. However, that said there is a lot in the “plus” column of the ledger here. The transverse leaf spring not only has less unsprung weight than a traditional IFS setup, but overall, it has a very good ride quality for its design with fewer suspension pieces in a simpler configuration. Will a straight axle front end with a transverse leaf spring pack win a Goodguys autocross? Not likely, but for a traditional hot rod build they are a must and can be made to run quite nicely while being safe on today’s roads.

How Do I Measure for The Correct Spring?

Spring length is determined by the axle width. So, if you do not have an axle in hand yet this can be a bit of a “cart before the horse” situation. As such, we recommend determining the correct straight axle kit for your street rod build with the amount of drop you want (if any). Our straight axle buyer’s guide will be a huge help in this regard to get you on your way to choosing the best axle for your project when shopping for your street rod parts. Once you have your solid axle of choice then you can determine what is the optimum spring length. Most axles will state on their product page or in their instructions what length spring to use, but for that barn find or swap meet straight axles you will need to confirm your spring mount center-to-center distance by measuring from the vertical spring perch mounting holes (center-to-center) on the axle and subtracting 5 inches.

For example, if your vertical spring perch mounting holes on your axle are 34 inches apart, you will need a leaf spring with 29 inches of free length, measured from the center of the spring’s eyes. This free length is measured from center-to-center of the leaf spring’s eyes, and not from the very end of the spring assembly. Conversely, if you have your spring perches and shackles already for your axle you can install them, level the shackles horizontally, and measure from the centerline of one shackle pin to the other. This will give you the direct spring length measurement you need, as the perches and shackles take up the 5-inch measurement deduction we previously mentioned.

While discussing spring measurement we cannot forget to discuss leaf spring free arch. The free arch of a leaf spring is defined as the measurement from the center of the spring eyes to the bottom surface of the leaf spring pack. The easiest way to take this measurement is to place the spring standing upright on the floor. Measure from the underside of the spring pack to the floor. Then measure from the spring eye’s center point to the floor. Subtract this second measurement from your first and it will give you the spring’s free arch.

What Is the Best Spring Material, Steel or Composite?

Both steel and composite leaf springs have been used in front and rear suspension systems for decades. From basic sedans to sports cars, steel and composite leaf springs have been a part of typical leaf spring suspension design. For our discussion on transverse straight axle leaf springs the majority of what is available today are steel leaf springs. While Speedway Motors does carry composite leaf springs, our current product line is mainly relevant to muscle car-era leaf spring rear suspensions. None the less, we do want to discuss both types of leaf springs here.

The typical steel leaf spring is made up a spring pack with anywhere from 3 or more individual leaves that are clamped and bolted together. Steel leaf springs are the most common style of leaf used in automotive suspension systems due to their load capacity and low cost. Their service life is quite long and in fact are still used today for things like car trailers. One of the main reasons new car manufacturers moved away from leaf springs was packaging. Automakers could provide smaller/tighter packaging using other suspension spring offerings versus the traditional leaf spring.

Composite leaf springs were designed to save weight and manufacturing costs, since composite leaf springs are usually a single leaf and not made up of a “spring pack” like a steel leaf spring. Though more expensive than a steel leaf spring, composite springs are known for having more consistent spring rates and extended service life. Today you will usually only find composite springs in performance rear suspension packages.

Which leaf spring is better, Multi Leaf or Mono Leaf?

As we have previously discussed in this buyer’s guide, multi leaf springs that make up a spring pack are indeed the most common leaf spring style and have been in use on everything from horse drawn carriages in the 18th century to automobiles in the 19th century. They have a high load capacity that can be adjusted by removing or adding leaves to the spring pack. Adding or removing leaves also will change ride height slightly, all other things being the same. Often cars with a light front end (Model Ts for example) or fender-less cars, can get away with fewer leaves in the spring pack without altering ride height while a heavier car (full body, larger engine) can easily be supported by adding leaves to the spring pack. Adding leaves will make a spring stiffer as well, reducing ride quality while improving capacity.

A mono leaf spring is exactly as its name sounds; a leaf spring made up of a single leaf that supports the vehicle’s weight. These leaf springs are usually a tapered design with a thick center that gets thinner out towards the spring eye ends. Since it is a single spring there is no option for adding or removing leaves to adjust ride quality/load capacity or ride height. This must be accomplished with additional add on components like coilover shocks, helper springs, or air springs. Speedway Motors does offer some front suspension solid axle transverse mono leaf springs, but they are much more suited to light front ends like a fender-less Model A.

What is The Difference Between Standard and Reverse Spring Eyes?

Looking at a transverse solid axle leaf spring, be it multi leaf or mono leaf, the spring eye is the “loop you see at each end of the spring and is what attaches to the shackles. A standard spring eye style is when the primary leaf in the spring pack has its ends rolled down. This is most of the springs you will find available and is how most stock applications are fitted.

Standard Eye Spring Design

A reverse spring eye sounds just like what you would think it is, where the primary leaf spring ends are rolled facing up, or reverse. The main reason a spring eye is reversed is for ride height. Repositioning the spring eye higher by reversing it will lower the ride height simply by swapping a standard spring eye for the reverse version of the same spring specs. You get a slightly lower ride height without compromising spring strength, load capacity, or ride quality. If you are looking for just a small front drop, often swapping a standard leaf spring for one with reverse spring eyes is typically good for about 1 inch in ride height.

Reverse Eye Spring Design

What Spring Eye Bushing Style is Best?

Spring eye bushings have been made from numerous materials over the decades, including bronze, nylon, polyurethane, and good old-fashioned rubber. Each bushing style provides a direct connection between the spring eye end of the leaf spring and the shackle and spring perch on the straight axle of your hot rod. They vary in stiffness and load capacity and the ability to provide some misalignment in the front suspension mounting. Each style is outlined below.

Bronze

Solid metal bushing is the stiffest option available
Excellent for high load applications
Long service life
No absorption of vibration or harshness
Does not allow for any misalignment

Nylon

Solid nylon bushing is very stiff but offers a slight amount of deflection
Works well for medium to high load applications
Medium service life
Very little absorption of vibration or harshness
Allows for a very small amount of misalignment

Polyurethane

Medium stiffness and offers a moderate amount of deflection
Works well for medium to high load applications
Long service life
Moderate absorption of vibration or harshness
Allows for a moderate amount of misalignment

Rubber

Softest of all bushing materials and offers the most amount of deflection
Works well for low to medium load applications
Shortest service life of all material options
Excellent absorption of vibration or harshness
Allows for the largest amount of misalignment of all bushing material options

What Is a Super Glide or Super Slide Spring?

These two leaf spring models are offered by Speedway Motors and Posies respectively. The leaf springs start as a multi leaf design that utilize small nylon pads or buttons sandwiched between the tips of each leaf spring in the spring pack. These nylon pads/buttons act as a self-lubricated anti-friction device between each leaf spring for a quieter and smoother ride. The majority of our Super Glide and Super Slide leaf springs are offered in reverse spring eye configurations and in various lengths and spring rates, however we do offer a select few options in standard spring eye fitment for those wishing for a more traditional look and ride height.

Determining the right spring for your traditional solid axle suspension hot rod build is not difficult with a little forethought and planning and the help of our Toolbox buyer’s guides. So let us help you get your hot rod parts ordered so you can get to building!

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